// {app_root}/config/plugin.js
exports.tracker = {
  enable: true,
  package: 'egg-tracker',
}

// {app_root}/config/config.default.js
exports.tracker = {
  format: 'random', // 32 byte random string or uuid string, random as default（数据格式，默认为32字节字符串）
  autoGenerateSpanId: true, // Enable auto generate span-id (默认开启自动生成span-id)
  autoGenerateParentSpanId: false, // Disable auto generate parent span-id (默认关闭自动创建parent span-id)
  key: 'tracker', // key of tracker object to attach to ctx/ctx.request/ctx.response
}

exports.middleware = ['tracker'] // Enable tracker middleware

// {app_root}/controller/index.js

const Controller = require('egg').Controller

class HomeController extends Controller {
  /**
   * Get tracker object through ctx, ctx.request or ctx.response.
   *
   * @params {string} tracker.traceId      - generate by plugin automatically if http headers doesn't include trace-id.
   * @params {string} tracker.spanId       - generate by plugin automatically.
   * @params {string} tracker.parentSpanId - get from http header of span-id.
   *
   * @memberof HomeController
   */
  async index() {
    this.ctx.body = this.ctx.tracker
  }
}

module.exports = HomeController